Pint-Sized
Science: Number Magic
By Sandy Fleming
Many people don't realize
it, but numbers are a big part of science. Numbers
also can be studied in their own right. The number system has
rules and patterns that can be used to perform some amazing tricks.
This sort of number play can help intrigue a student with math,
and
can even provide a social boost as the child takes these activities and tricks and uses them to amuse and confound friends.
In order to do these tricks
independently, your child will need to be
proficient at the basic operations of math: addition, subtraction,
multiplication and division. It would be quite embarrassing to
try a
math trick in front of friends and mess up because of a computation
error! Younger or less experienced kids can also use calculators
if
you wish.
Try these mathematical marvels!
Unlucky Numbers:
Choose any number with less than eight digits. Double it, then
add
15. Multiply the answer by 3 and add 33 more. Now, divide by
6 and subtract
the original number. The answer will always be 13!
Subtraction Predictions:
Pick a three-digit number whose digits are in reverse counting
order,
like 987 or 432. Write it down. Now, reverse that number and
write it
below the first. Subtract the lesser number from the greater.
The
answer will always be 198.
You can do the same trick
with 4-digit numbers (like 8765) and the
answer will always be 3087.
These tricks can be fun
mind-reading games. Magicians can write predictions of the
answers down ahead of time, or solve the problems
faster than friends can type them into a calculator.
Mind-Reading Magic:
Use five pieces of paper. Write the number 1 on one side of a
piece
and 2 on the other side. Write a 3 on one side of the next paper
and a 4 on the other side of that. Write 5 and 6 in the same
way on the third paper, 7 and 8 on the fourth paper, and 9
and 10 on the fifth. Ask a friend to lay out all five cards with
either side facing upwards and tell the magician (who has eyes
closed!) how many odd numbers are visible. The magician will
be able,
without looking, to tell the total of the visible numbers! How?
All
he or she needs to do is subtract the number of odd numbers visible
from 30. For example, if the numbers showing are 2, 3, 6, 8,
9,
there are two odd numbers showing (3 and 9). The total of 2+3+6+8+9
is
28, and 30-2 odd numbers is also 28!
You'll find other math
tricks galore in your local library or bookstore. Some books
to check out include Mathemagic by Raymond
Blum
from Sterling Publishing Company, The Magical Math Book by
Bob Longe,
and Math Magic: Slick Tricks with Numbers by Margaret
Thomas. Websites
that focus on math also abound! Check out these gems for more
mathematical fun and games:
http://www.eduplace.com/index.html
http://www.aaamath.com
http://www.coolmath.com
Sandy Fleming
is an educator, author and workshop facilitator. She resides
in southern Michigan with her husband and three daughters.
Sandy leads workshops for daycare providers and parents
in the region, tutors students, volunteers for Girl Scouts
and her church, and teaches online classes for adults and
children. She loves to make new friends, so please drop
her an e-mail at kids@busyparentsonline.com
